1) Field of the Invention
The present invention generally relates to a technique for manufacturing brick, and in particular to a system for extruding paver brick having textured faces about the edges.
2) Description of the Prior Art
Brick are make either by molding or extruding. Molding is much slower and is primarily used for special shapes and textures. Paver brick are solid brick, laid flat so that the exposed faces of the brick form the surface of a floor, walkway, patio or street. Molded pavers typically have a chamfer or radius edge around the exposed face. Preferably the edges of the opposite parallel face also have a chamfer or radius.
Textured edges around the face of a paver brick have several advantages over sharp edges: 1) textured edges provide a more desirable appearance to the surface; 2) texture edges are more comfortable to walk upon; 3) sharp edges chip more easily in handling at the factory, in shipment, and at the job site, resulting in higher losses than for textured edges; 4) textured edges produce a paver having both faces chamfered or radiused at the edges and, if damage occurs to one face, the other face is still usable; and 5) textured edges command a higher price in the marketplace.
Unfortunately, the manufacturing cost is much higher for a molded brick than an extruded brick. Molded brick presses are expensive, produce fewer brick per hour, are labor intensive, and are difficult to automate. On the other hand, prior art extruded pavers have sharp or untextured edges of the face due to the geometry of the extruder die and the method of cutting the extruded slugs.
Early roll-edge cutters have textured extruded slugs along a single axis of the brick by pushing the brick through rollers. The Lingl (U.S. Pat. No. 3,468,998) is representative of the use of notching rolls to improve the surface appearance of a slug which is cut by being pushed through wires. Some older designs may have tried to texture along two axis by making two or e pushes at right angles on the slug.
The Kenworthy (U.S. Pat. No. 4,436,501) teaches a method and apparatus of producing special brick shapes such as corner brick. Slugs are pushed from an off-bearing belt under surface treatment means and onto an elevator. A cutter box or frame is located above the elevator. The frame includes both cutter means to cut the slugs into a desired shape and surface treatment means for treating the side edges of the slugs. The elevator raises the slugs up through the cutter frame to a position in alignment with a discharge platform. A pusher assembly operates to push the slugs from the off-bearing belt to the elevator and to push the cut slugs from the elevator onto the discharge platform.
The Brugger et al. (U.S. Pat. No. 4,311,073) teaches an improved method and apparatus for cutting an extruded clay column into individual brick moldings. A conveyor brings the uncut slug into a predetermined position underneath the cutting device. The uncut portion is then transferred to the lifting table. The slug is cut by a plurality of cutting wires secured in the frame which is lowered with respect to the lifting table so that the wires pass through the clay. The frame is then raised to its starting position and the cut slugs are redeposited on the conveyor.
The Gross (U.S. Pat. No. 4,340,557) teaches a method for removing surface defects from plastic blanks. The method includes providing a sheet of polymeric material, pressing lines of demarkation upon the sheet by passing the sheet through a pair of embossing rolls, severing the sheet within the lines to separate and cutting the sheet into individual blanks.
Certain disadvantages become apparent from a close review of these references. For example, multiple pushes or moves through the cutter result in low production rates and high maintenance costs for the cutter. Alternatively, the texturing, grooving and/or edge rolling must be performed by cutters or grooving tools mounted above an intermediate platform.
It has thus become desirable to develop an improved technique for manufacturing brick, and in particular to a system for extruding paver brick having textured faces about the edges without adding movement or increasing production, thereby permitting production by extrusion at a corresponding much lower cost than molding.